Respuesta :
The right answer for the question that is being asked and shown above is that: "D. Not Affected By." People keep spending additional units of a particular resource on a want until their marginal benefit is Not Affected By their marginal cost.
The correct option is D.
Marginal cost refers to the amount of money it cost a company to produce one more of a particular product while the marginal benefit refers to the benefit that is obtained as a result of producing that one extra product. Profit is maximized when the marginal cost equals the marginal benefits.